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Nuclear mRNA accumulation causes nucleolar fragmentation in yeast mtr2 mutant
1Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106.
Molecular Biology of the Cell
|November 1, 1994
Summary
The MTR2 gene is crucial for mRNA export in yeast. Its mutation causes nuclear mRNA accumulation and nucleolar disorganization, impacting protein synthesis.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- mRNA export is vital for gene expression.
- The Saccharomyces cerevisiae nucleus is a complex organelle.
- Specific proteins regulate the transport of RNA molecules.
Purpose of the Study:
- To identify genes involved in mRNA transport (mtr) in yeast.
- To characterize the function of the MTR2 gene and its protein product.
- To investigate the relationship between mRNA export, nuclear organization, and protein synthesis.
Main Methods:
- Gene identification and cloning of MTR2.
- Analysis of mtr2-1 mutant phenotypes at 37°C.
- Localization studies of polyA+RNA and nucleolar antigens.
- Assessment of RNA synthesis, processing, and export.
- Evaluation of protein synthesis inhibition.
Main Results:
- MTR2 encodes a novel 21-kDa nuclear protein essential for growth.
- mtr2-1 mutants accumulate polyA+RNA in nuclear foci at 37°C.
- Nucleolar antigens redistribute to these foci, dependent on RNA polymerase II transcription.
- Despite ongoing RNA synthesis and processing, protein synthesis is inhibited.
Conclusions:
- MTR2 plays a critical role in nuclear mRNA export.
- Nuclear mRNA accumulation leads to nucleolar disorganization.
- The yeast nucleolus may be involved in mRNA export regulation.